Plastics recycling method is alternative to mechanical

VTT Technical Research Centre of Finland says that it is researching chemical recycling of plastics based on pyrolysis, which can turn nearly all plastics and their mixtures into oil.

According to the organization, while mechanical recycling suits most plastic bottles, bags and wraps, 40–60% of separately collected plastic waste in Finland does not qualify for this type of recycling and ends up incinerated.

‘By chemical recycling, however, plastics and their mixtures can be broken down into separate raw materials, whose quality is equal to that of respective virgin materials,’ said Anja Oasmaa, senior principal scientist at VTT.

According to VTT, chemical recycling offers an ecologically sound alternative to incineration and possibly to mechanical recycling as well. Current legislation in Finland and the EU does not recognise chemical recycling of plastics as being equal to mechanical recycling.

The pyrolysis involves heating long polymer chains of plastics and their mixtures in the absence of oxygen, thus chopping them into shorter chains and in part even to monomers. The resulting pyrolysis wax or oil could be processed with traditional methods at oil refineries, VTT says.

‘Pyrolysis oil can be distilled into separate monomers, diesel and other fractions, some of which can be used directly as fuels and some as raw material for plastics and other chemicals,’ added Oasmaa.

VTT says that it is also looking into the recycling of polystyrene, the removal of hazardous compounds from plastic waste and the production of diesel fuels from plastic waste to be used in power generation and marine transport.

This story uses material from VTT, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier.